This invention relates generally to power modules for multi-chip printed circuit boards.
Many modern integrated circuit chips, such as microprocessors for example, require relatively high supply current delivered at a very tightly controlled voltage. It is common, therefore, to employ a special-purpose module including voltage converters, voltage regulators and the like to supply power to such a chip. And it is known that disposing the power module physically close to the supplied chip helps to reduce negative effects associated with the delivery of power via cables.
Recently it has become popular to deploy two or more high-power chips on a single multi-chip printed circuit board. Among the problems presented by this approach is how to dispose the power module sufficiently close to the supplied chips while at the same time providing adequate thermal management for the supplied chips and conserving space on the printed circuit board.
It is an object of the present invention to provide a power module for a multi-chip printed circuit board such that: (1) the power module is disposed physically close to the chips on the printed circuit board, (2) thermal management is provided for the supplied chips, and (3) space is conserved on the printed circuit board.
In a power module assembly according to a preferred embodiment of the invention, a heat distribution plate is provided having first and second fields of receptacles integrally formed therein. The receptacles are populated with first and second fields of thermally-conductive pins capable of moving independently in a direction orthogonal to the plate. A power module printed circuit board is mounted to the heat distribution plate and has first and second clearance holes formed therein. The first and second fields of pins protrude through the first and second clearance holes. A multi-chip printed circuit board may be mounted underneath the power module such that the thermally-conductive pins contact a surface of first and second supplied chips. In this manner, the supplied chips are physically close to the power module, and thermal management for the supplied chips is provided by virtue of contact between the supplied chips and the thermally-conductive pins. Z-axis compliance provided by the pin/receptacle assemblies enhances thermal conductivity even when the supplied chips have differing heights relative to the top of the multi-chip printed circuit board. Space on the multi-chip printed circuit board is conserved because the power module is not part of the multi-chip printed circuit board, but rather is mounted on a separate printed circuit board disposed over the top of the multi-chip printed circuit board.